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  1. #1
    RC Qualifier
    Join Date
    Apr 2013
    Location
    Portland, OR
    Posts
    677

    Lipo cells out of balance after discharge

    Hey guys,
    I couldn't find where this question had been asked before, but I'm sure it has, so sorry in advance for asking a repeat question.
    I'm running 6500 & 5000 mah 2S Lipo batteries in my Slash 4x4. Once LVC is reached and I put the batteries on the charger, I see that there seems to be a large amount of variance in the volts per cell of each of the two cells. For example at full charge (I always balance charge) each cell is at 4.2 volts per cell but after discharge it is not uncommon for the charger to read a difference of as much as .3 volts per cell difference between the two (3.55 vpc on cell 1 and 3.25 vpc on cell 2). Usually the difference is much less than that, usually in the .1 - .15 volt per cell area, but I'm wondering if that variance is normal or something I should be keeping an eye on.
    So my question is what is a normal difference in volts per cell between cells after discharge?

    Some possibly relevant information:
    -I always balance charge, no exceptions
    -The batteries have never been hot or even warm to the touch after discharge
    -The batteries have always been stored at proper voltage
    -The batteries are in good condition and have not had any major trauma
    -One battery is 2 months old, the other is 2 weeks old
    -I only charge at 4amps (less than 1C)

    Any input would be helpful. Thanks!

  2. #2
    RC Turnbuckle Jr. JimmyNeutron's Avatar
    Join Date
    Oct 2009
    Location
    Alma, Michigan
    Posts
    12,316
    The variance is normal... and is the reason why balance charging every time is important.
    Whatever it is I just typed... could be wrong.

  3. #3
    Marshal Double G's Avatar
    Join Date
    May 2008
    Location
    Putting the wet stuff on the hot stuff
    Posts
    10,521
    Best to contact the manufacturer of the batteries.
    The Super Derecho

  4. #4
    Marshal ksb51rl's Avatar
    Join Date
    Nov 2006
    Location
    Northern NJ
    Posts
    17,388
    As said, you should contact the dealer.
    However, looking at your cell voltages, it is very obvious that you have over-discharged and therefore damaged the packs.
    Sorry.
    Alt-248 on the number pad =

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